LOW CYCLIC ALTERNATING PATTERN RATE AS AN INDICATOR OF MIGRAINE WITHOUT AURA IN SCHOOL-AGED CHILDREN

Introduction Primary headaches are closely related to sleep. Great modifications in the arousal patterns during sleep have been reported in migraine, especially in the nights preceding a headache attack. Aim of the study was to evaluate the pattern of arousal from sleep in a group of migraine school-aged patients. Materials and methods Population study consisted of 5 patients, (four females and one male), aged 8-15 years (mean 11.7 years, SD±2.43), affected by migraine without aura (MO), according to ICHD-II criteria, who referred to the third University Level Headache Centre for Developmental Age of the Department of Child and Adolescent Neuropsychiatry of the Second University of Naples. All the mothers of the subjects were asked to fill in the Sleep Disturbances Scale for Children (SDSC) questionnaire to assess the presence of sleep troubles. Patients underwent three overnight polysomnographic studies, following adaptation; arousal pattern was studied by the scoring of the cyclic alternating pattern (CAP). Results Migraineurs showed a lower CAP rate in non-rapid eye movement (NREM) sleep (CAP rate mean value 14.875% vs. 24.56% of matched control, p=0.005) and, in particular, a lower number of A1 phases, as shown in a recent report in an adult population. The reduction in the CAP rate indicates a lower level of arousal fluctuation in NREM sleep, suggesting a dysfunction in neural structures involved in both the control of REM sleep and the pathophysiology of migraine, such as the hypothalamus and the brainstem. Discussion In the last 30 years, the intimate relationship between sleep and headache has been recognized even if the relationship remains clinically and nosologically complex, and widely obscure. Headaches associated with nocturnal sleep have often been perceived as either the cause or result of disrupted sleep. Recent biochemical and neurofunctional imaging studies in patients with primary headache disorders has lead to the identification of potential central generators which are also important for the regulation of normal sleep architecture and sleep microstructure and could be an important tool to clarify the relation between the two. Conclusions The relationship between headaches and sleep disturbances is complex and difficult to analyse, but neurophysiological tools and sleep study (both macrostructural and microstructural) could be useful to clarify this obscure aspect of two so frequent clinical events, particularly in school-aged children.